/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.druid.server.coordinator.duty;

import org.apache.druid.server.coordinator.DruidCoordinatorRuntimeParams;

import javax.annotation.Nullable;

/**
 *
 */
public interface CoordinatorDuty
{
  /**
   * Implementations of this method run various activities performed by the coordinator.
   * Input params can be used and modified. The returned DruidCoordinatorRuntimeParams is passed to the next duty.
   *
   * @return same as input or a modified value to be used by next duty. Null return
   * values will prevent subsequent CoordinatorDuty objects (see the order in the lists passed into the constructor of
   * {@link org.apache.druid.server.coordinator.DruidCoordinator.DutiesRunnable}) from running until the next
   * cycle.
   */
  @Nullable
  DruidCoordinatorRuntimeParams run(DruidCoordinatorRuntimeParams params);
}
